Portable apparatus for detecting breast cancer

ABSTRACT

An apparatus for detecting abnormal masses such as breast cancer includes a measurement sensor configured to obtain a voltage at a first area of a first breast of a subject; a reference sensor configured to obtain a voltage at a second area of a second breast of the subject, a position of the first area corresponding to a position of the second area; and a detector, wherein the detector includes a differential amplifier configured to amplify a voltage input from the at least one of the measurement sensor and the reference sensor; an active low pass filter configured to pass a signal frequency of a low frequency band among signals transmitted from the differential amplifier; a driver amplifier configured to amplify a signal passed through the active low pass filter; and an analog-to-digital (AD) converter configured to convert the signal amplified by the driver amplifier into a digital signal.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Continuation-In-Part Application of International ApplicationNo. PCT/KR2015/012619, filed on Nov. 24, 2015, which claims priorityfrom Korean Patent Application No. 10-2015-0164352, filed on Nov. 23,2015, in the Korean Intellectual Property Office, the disclosures ofwhich are incorporated herein in their entireties by reference.

BACKGROUND

1. Field

Apparatuses consistent with the exemplary embodiments relate to aportable apparatus for detecting abnormal masses of a tissue, such asbreast cancer (e.g., handheld breast cancer screening device), and morespecifically, to a portable apparatus capable of detecting breast cancerby setting a reference signal for a differential amplifier based on onepoint in a breast area instead of using a right leg driver (RLD).

2. Description of the Related Art

Breast cancer is a disease that is frequently found in females. It ispossible to increase the survival rate of females with breast cancerwhen the breast cancer is diagnosed and treated at an early stage.However, since there is no prognosis at an early stage of breast cancerin many cases, it is not easy to confirm breast cancer. While breastcancer screening may be performed through regular health screening, itis difficult to distinguish breast cancer from a cyst or a breast tissuegrowth when a size of the tissue is not large. Therefore, when the sizeof the tissue is a certain size (e.g., about 10 mm) or greater, precisediagnosis is performed by using various diagnostic devices such asX-ray, ultrasound, and magnetic resonance imaging (MRI). In the relatedart, a breast cancer screening method is disclosed in Korea PatentApplication Nos. 10-2009-0096934 and 10-2008-0004564. One example is touse X-rays to detect the presence of a lesion of a breast and amicrocalcification lesion, but the procedure often give the subject adiscomfort or pain because it is performed while the breast is pressed.

Normal somatic cells in a human body undergo a division processincluding a resting stage and a differentiating stage. In this case, acell membrane is open and an ion exchange with tissues of other cells isactive in a cell during the division process, and thus a potentialdifference between the cell membrane and basal tissue increases. Ingeneral, in a normal cell, a potential difference is about −70 mV at theresting stage and −15 mV at the differentiating stage. On the otherhand, similarly to the normal cell, a cancer cell is also differentiatedthrough a normal process. However, unlike the normal cell, the cancercell has a differentiation time that is about half of a differentiationtime of the normal cell, and the differentiation time of the cancer cellis about one hour. However, since a normal cell has a function ofregulating overdifferentiation in cell tissue, the cell tissue remainsin a certain shape and size. However, a cancer cell proliferatesinfinitely because the cancer cell does not have such a regulatingfunction. About 1 million of cancer cells are necessary to form a cancertissue having a diameter of about 1 cm. Among them, about 30,000 cancercells are differentiated daily without cell death, and a potentialdifference of −15 to −40 mV is consistently maintained in a malignanttumor through such differentiation. When such a potential difference isdetected, it is possible to distinguish tumor tissue having a smallsize.

In a method of the related art disclosed in Korean Patent No.10-0794721B, a presence of an abnormal tissue and/or abnormal cellularactivities are detected by measuring an amount of change in acapacitance of a biosensor according to a change in an electromagneticfield of a human body input through a biosensor and then converting adeviation from a reference value into a deviation of a frequency formeasurement Also, in a method of the related art disclosed in KoreanPatent No. 10-0794721B, a measurement time of about 30 minutes isnecessary to obtain a balance of a biological signal when the biologicalsignal is measured.

SUMMARY

One or more exemplary embodiments provide a portable apparatus fordetecting abnormal masses of a tissue (e.g., breast cancer), capable ofaccurately diagnosing abnormal masses of a tissue in one breast in ashort time by setting a reference signal based on a corresponding pointof an area of another breast and electrically connecting a right legdriver (RLD) circuit to a differential amplifier within the apparatus,instead of directly connecting a ground circuit to a ground point (e.g.,an end point of a right leg) of a human body.

According to an aspect of an exemplary embodiment, there is provided anapparatus for detecting abnormal masses of a tissue, wherein theapparatus includes a measurement sensor configured to obtain a voltageat a first area of a first breast of a subject; a reference sensorconfigured to obtain a voltage at a second area of a second breast ofthe subject, a position of the first area corresponding to a position ofthe second area; and a detector, wherein the detector includes adifferential amplifier configured to amplify a voltage input from the atleast one of the measurement sensor and the reference sensor; an activelow pass filter configured to pass a signal frequency of a low frequencyband among signals transmitted from the differential amplifier; a driveramplifier configured to amplify a signal passed through the active lowpass filter; and an analog-to-digital (AD) converter configured toconvert the signal amplified by the driver amplifier into a digitalsignal.

The differential amplifier may amplify a difference between voltagesrespectively obtained by the measurement sensor and the referencesensor.

The detector may further include an overvoltage and/or overcurrentprotection circuit configured to block a leakage current from anoutside.

A ground operating circuit may be electrically connected to thedifferential amplifier.

At least a part of the ground operating circuit may be of an open looptype.

The ground operating circuit may include an operational amplifier havingtwo input terminals that are electrically connected to the differentialamplifier and a reference voltage, respectively; a resistor electricallyconnected between the operational amplifier and an output voltage; afirst capacitor electrically connected between the differentialamplifier and the output voltage; and a second capacitor electricallyconnected between the operational amplifier and the output voltage.

The ground operating circuit may be electrically connected to theplurality of the differential amplifiers.

A signal frequency of the low frequency band may be about 50 Hz or less.

The apparatus may further include a controller electrically connected tothe AD convertor and may store an algorithm for calculating the digitalsignal converted by the AD converter and determining a lesion.

The controller may further include: a sensor signal average moduleconfigured to obtain an average value of sensor signals of at least oneof the measurement sensor and the reference sensor; a sensor positioncorrection module configured to detect a signal value that exceeds anallowable range and determine whether to change a position of a sensoramong the measurement sensor and the reference sensor; a sensor failuredetermination module configured to determine a failure in the sensor;and a lesion primary screening module configured to determine the lesionbased on the average value of the sensor signals.

When a difference between An(t), which is the average value of thesensor signals input in a certain time interval (t), and a specificsignal value (Dn) among a plurality of signal values input in thecertain time interval (t) is equal to or greater than a specific value,the sensor signal average module may exclude the signal value inobtaining the average value of the sensor signals.

An(t), which is the average value of the sensor signals input in acertain time interval (t) may be obtained, and the sensor positioncorrection module may be activated when a number of a sensor value (Vn)exceeding ±3.5 mV based on An(t) has a certain ratio or higher withrespect to a total number (M) of the sensor signals.

An(t), which is the average value of the sensor signals input in acertain time interval (t) may be obtained, and the sensor failurechecking module may be activated when a number of times a sensor value(Vn) exceeds ±3.5 mV based on An(t) has a certain ratio or higher withrespect to a total number of sensing values (M) of the sensor signals.

The primary screening module may determine normality in response to theaverage value of the sensor signals being less than 7 mV, and determineabnormality in response to the average value being in a range from 14 mVto 20 mV.

The apparatus may further include a peripheral sensor configured toobtain a voltage around an area, of the first breast, at which themeasurement sensor is positioned.

The differential amplifier may amplify a difference between voltagesrespectively obtained by the peripheral sensor and the reference sensor.

The reference voltage may be determined by setting one of sensor signalsof at least one of the measurement sensor and the reference sensor as areference signal.

According to an aspect of an exemplary embodiment, there is provided anapparatus for detecting abnormal masses of a tissue, wherein theapparatus includes at least one first sensor configured to obtain avoltage at a first position of a first breast of a subject; at least onesecond sensor configured to obtain a voltage at a second position of asecond breast of the subject, the second position corresponding to thefirst position; a differential amplifier configured to amplify adifference between voltages respectively obtained by the at least onefirst sensor and the at least one second sensor; and a lesiondetermination controller configured to determine whether a lesion ispresent based on an output of the differential amplifier.

The apparatus may further include a ground operating circuit iselectrically connected to the differential amplifier, wherein the groundoperating circuit provides a ground by setting one of sensor signals ofthe at least one first sensor and the at least one second sensor as areference signal.

According to an aspect of an exemplary embodiment, there is provided anapparatus for detecting abnormal masses of a tissue, wherein theapparatus includes a measurement sensor configured to obtain a voltageat a first area of a first breast of a subject; (n−1) number ofperipheral sensors configured to obtain a voltage around the first area,n being an integer equal to or greater than two; a reference sensorconfigured to obtain a voltage at a second area of a second breast ofthe subject, a position of the first area corresponding to a position ofthe second area; n number of differential amplifiers configured torespectively amplify differences between the voltage obtained by thereference sensor and voltages obtained by the measurement sensor and the(n−1) number of peripheral sensors, wherein a presence of a lesion isdetermined based on outputs of the n number of differential amplifiers.

According to an aspect of an exemplary embodiment, there is provided amethod of detecting abnormal masses of a tissue, wherein the methodincludes obtaining, by a measurement sensor, a voltage at a first areaof a first breast of a subject; obtaining, by a reference sensor, avoltage at a second area of a second breast of the subject, a positionof the first area corresponding to a position of the second area; andamplifying, by a differential amplifier, a voltage input from the atleast one of the measurement sensor and the reference sensor; passing,by an active low pass filter, a signal frequency of a low frequency bandamong signals transmitted from the differential amplifier; amplifying,by a driver amplifier, a signal passed through the active low passfilter; and converting, by an analog-to-digital (AD) converter, thesignal amplified by the driver amplifier into a digital signal.

According to an aspect of an exemplary embodiment, there is provided amethod of detecting abnormal masses of a tissue, wherein the methodincludes obtaining, by at least one first sensor, a voltage at a firstposition of a first breast of a subject; obtaining, by at least onesecond sensor, a voltage at a second position of a second breast of thesubject, the second position corresponding to the first position;amplifying, by a differential amplifier, a difference between voltagesrespectively obtained by the at least one first sensor and the at leastone second sensor; and determining, by a lesion determinationcontroller, whether a lesion is present based on an output of thedifferential amplifier.

According to an aspect of an exemplary embodiment, there is provided amethod of detecting abnormal masses of a tissue, wherein the methodincludes: obtaining, by a measurement sensor, a voltage at a first areaof a first breast of a subject; obtaining, by (n−1) number of peripheralsensors, a voltage around the first area, n being an integer equal to orgreater than two; obtaining, by a reference sensor, a voltage at asecond area of a second breast of the subject, a position of the firstarea corresponding to a position of the second area; and amplifying, byn number of differential amplifiers, respective differences between thevoltage obtained by the reference sensor and voltages obtained by themeasurement sensor and the (n−1) number of peripheral sensors, wherein apresence of a lesion is determined based on outputs of the n number ofdifferential amplifiers.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become apparent and more readilyappreciated from the following description of exemplary embodiments,taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram showing a method of measuring a biologicalsignal in a comparative example.

FIG. 2 is a schematic diagram showing a measurement method used by aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 3 is an exemplary diagram showing a portable breast cancerdetection apparatus and a sensor unit according to an exemplaryembodiment.

FIG. 4 is an exemplary diagram showing an example of using a portablebreast cancer detection apparatus and a sensor unit according to anexemplary embodiment.

FIG. 5 is a configuration diagram showing components of a portablebreast cancer detection apparatus according to an exemplary embodiment.

FIG. 6 is a detailed circuit diagram showing a first amplifier and aground operating circuit that is electrically connected thereto in aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 7 is a detailed circuit diagram showing an active filter in aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 8 is a detailed circuit diagram showing a second amplifier in aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 9 is an interface screen showing a form in which a signal isprocessed and changed when the signal has passed a data processing unitof a portable breast cancer detection apparatus according to anexemplary embodiment.

FIGS. 10 and 11 are flowcharts illustrating a process of transmitting asignal passing through a digital filter of a data processing unit to acomputation unit to detect a lesion according to an exemplaryembodiment.

FIGS. 12 and 13 are schematic diagrams showing processes performed by aplurality of sensor units according to an exemplary embodiment todetermine a relative position with respect to a position of a malignanttumor and measure a biological signal based thereon.

FIGS. 14 to 17 are interface screens in which a screening result of datameasured by a portable breast cancer detection apparatus according to anexemplary embodiment is provided

DETAILED DESCRIPTION

While the exemplary embodiments are susceptible to various modificationsand alternative forms, specific embodiments thereof are shown in thedrawings and described in detail below. However, it should be understoodthat there is no intention to limit the disclosure to the particularforms disclosed, and that the disclosure covers all modifications,equivalents, and alternatives falling within the spirit and scope of thedisclosure.

Like numbers refer to like elements throughout the description of thefigures. Sizes of elements in the drawings may be exaggerated forclarity. It should be understood that, although the terms “first,”“second,” etc. may be used herein to describe various elements, theseelements are not limited by these terms. These terms are only used todistinguish one element from another. For example, a first element couldbe termed a second element, and similarly, a second element could betermed a first element, without departing from the scope of thedisclosure. Elements of the invention referred to in the singular maynumber one or more unless clearly indicated otherwise by context.

It should be understood that the terms “comprise,” “comprising,”“include,” and/or “including” specify the presence of stated features,numbers, steps, operations, elements, components, and/or groups thereofwhen used herein, but do not preclude the presence or addition of one ormore other features, numbers, steps, operations, elements, components,and/or groups thereof. Also, it should be understood that, when a partsuch as a layer, a film, an area, or a plate is referred to as being“formed on” on another part, the part can be “formed directly” on theother part or intervening parts may be present. On the other hand, whena part such as a layer, a film, an area, or a plate is referred to asbeing “formed below” on another part, the part can be “formed directlybelow” the other part or intervening parts may be present.

Hereinafter, exemplary embodiments will be described in further detailwith reference to the accompanied drawings.

The term “biological signal” herein refers to a signal generatedaccording to an electrochemical activity of cells of nervous tissue,muscular tissue, and glandular tissue. Electrically, this “biologicalsignal” of the cells appears when a resting potential and an actionpotential are generated. A breast cancer cell and a normal cell aredifferent for various reasons, and have a difference in electrochemicalaspects. When a normal cell is in a resting stage after cell division iscompleted, a potential difference between a cell membrane and a basilarmembrane is maintained at a certain value. A living cell maintainsconcentrations of ions in the cell at constant values by exchanging ionsthrough a cell wall according to energy activity. Concentrations of ionsare changed between an inside and an outside of the cell wall, and apotential difference of a constant level of −70 mV is maintained betweenthe cell and a cell fluid. The potential difference is maintained onlyin the resting stage. When the cell starts division activity, the cellmembrane is deformed, and the potential difference is reduced to about−15 mV to 0 mV. When a normal cell has completed cell division, apotential difference of the normal cell is restored to an original valuethereof. However, unlike a normal cell, in a cancer cell, an active ionexchange does not occur in cancer tissue centered at the cell membrane,and the cancer cell has a biological signal of −40 mV to −15 mV due tooverdifferentiation.

FIG. 1 is a schematic diagram showing a method of measuring a biologicalsignal in a comparative example.

Referring to FIG. 1, in a medical device for measuring a biologicalsignal in a comparative example, a unipolar method and a bipolar methodcan be selectively used in order to use a differential amplifieraccording to an application of the signal. The bipolar method isexemplarily used in FIG. 1. A measured signal 1 refers to a differencevalue (V1−Vref) between a value measured at an area V1 and a referencesignal at a right leg (or right foot, or an end point of a right leg). Ameasured signal 2 refers to a difference value (V2−Vref) between a valuemeasured at an area V2 and a reference signal at the right leg. In thiscase, a differential signal value is a difference value (V1−V2) betweenthe measured signal 1 and the measured signal 2. The bipolar method ismore effective than the unipolar method in consideration of a resolutionof a signal. However, when the bipolar method is used, there is aproblem in that noise is frequently generated.

Also, when the unipolar method or the bipolar method is used, a rightfoot is used as a reference signal with respect to a signal to bemeasured. The right foot is a ground point of a human body when thehuman body and a measurement device are connected. A hand area can beused instead of the foot area. The ground point is a point connected toa reference signal of a device when a signal of the human body ismeasured. When a signal measured at the human body is transmitted to aninput end of the measurement device, a return path through whichremaining energy other than the signal to be transmitted is returned tothe human body needs to be formed. The ground under the right leg servesas a relay between measured signals. Therefore, it is possible todecrease common mode interference that occurs in a signal transmissionpath. However, there is a problem in that, when the right leg as areference signal is located farther from a measurement area, animpedance between two points increases, and a time required for thereference signal of the right leg to be in a steady state increases.This is because an impedance value in a homogeneous conductor isproportional to a length of the conductor. Also, when the number ofmeasured signal groups increases, a subtle performance difference causedby tolerance of each measurement device further increases a timerequired for the reference signal of the right leg to be in the steadystate, which results in problems in which a time required forstabilizing the signal increases and such an increased time causesthermal noise due to an increased temperature of the device so that itis difficult to measure the signal accurately.

FIG. 2 is a schematic diagram showing a measurement method in a portablebreast cancer detection apparatus without a ground position of a rightleg reference signal according to an exemplary embodiment.

Compared with FIG. 1, in an exemplary embodiment as shown in FIG. 2, inorder to obtain rapid stabilization of a signal, a measured signal isset as a reference signal without setting a right leg ground position.Therefore, it is not necessary to separately set a ground position at ahuman body, and thus measurement positions of V1 and V2 may becomecloser, to decrease an impedance. Accordingly, a signal can be furtherrapidly stabilized.

Instead of using a right leg operating circuit in FIG. 1, an exemplaryright leg operating circuit in the portable breast cancer detectionapparatus in FIG. 2 is connected to a reference voltage Vref for directstabilization. In this case, a direct voltage (DC) voltage is used asthe reference voltage to provide a voltage that serves as a referencefor the circuit. Also, according to an exemplary embodiment, thereference voltage may be lower than a bias voltage that is used in anamplifier circuit, and a voltage capable of providing a resolution toperform analog/digital (A/D) conversion may be provided.

When the circuit as shown in FIG. 2 is used, stabilization can beachieved at the same time as a time at which a power source of ascreening device is turned on. Therefore, it is possible to measure aflow of a measured signal rapidly and accurately. As an example, aprotection circuit having a symmetrical structure in which Z1 and Z2,which indicate impedances, have the same value and an impedance value is200 Kohm or more may be provided, but the exemplary embodiments are notlimited thereto. An output of a right leg driving circuit is notseparately connected and remains in a floating state.

FIG. 3 is an exemplary diagram showing a portable breast cancerdetection apparatus and a sensor unit according to an exemplaryembodiment. FIG. 4 is an exemplary diagram showing an example of using aportable breast cancer detection apparatus and a sensor unit accordingto an exemplary embodiment.

FIG. 5 is a configuration diagram showing components of a portablebreast cancer detection apparatus according to an exemplary embodiment.

FIG. 6 is a detailed circuit diagram showing a first amplifier and aground operating circuit that is electrically connected thereto in aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 7 is a detailed circuit diagram showing an active filter in aportable breast cancer detection apparatus according to an exemplaryembodiment.

FIG. 8 is a detailed circuit diagram showing a second amplifier in aportable breast cancer detection apparatus according to an exemplaryembodiment.

As shown in FIG. 3 and FIG. 4, a portable breast cancer detectionapparatus 1000 is a portable screening device, and may include a sensorunit 100 and a detector 200. The sensor unit may have a structure in theform of a cable to which a screening sensor is attached. The screeningsensor of the sensor unit 100 may include a hydrogel having highimpedance and metallic electrodes having high conductivity. Each of themetallic electrodes is electrically connected to a conductive cable andmay transmit an electrical signal to the breast cancer screening device.An exemplary material of a sensor includes an electrode having Ag/AgClplating and/or a half cell characteristic equivalent thereto. A hydrogelis a high impedance gel that connects an electrode and a human body andsuppresses an occurrence of an overcurrent.

The sensor unit 100 connected to the portable breast cancer detectingapparatus 1000 may include a measurement sensor unit (or a measurementsensor) 110, a plurality of peripheral sensor units (or a plurality ofperipheral sensors) 120, and a reference sensor unit (or a referencesensor) 130. In a measurement area inside the sensor unit 100, a voltageis generated in the sensor unit 100 when charging is performed due to anelectromagnetic induction phenomenon according to an action potential ofinner skin cells of a subject. The sensor unit 100 may detect aprecancerous change and an adjacent malignant tumor at an early stageusing a current-passing electrode. When the above electrode is used,structural information and functional information of a screening targettissue may be provided based on a measured value of a potentialdifference in a specific range frequency, and corresponding depth andlocal anatomical information may be provided. A direct current potentialdifference or an alternating current potential difference may bemeasured in abnormal tissue or cancerous tissue to confirm the presenceof abnormal precancerous cell tissue or cancerous cell tissue.

The measurement sensor unit 110 of the sensor unit 100 is a sensor thatis attached to one breast of the subject, and is a sensor that isattached to an area of the subject to check whether the area has a tumorand measure a biological signal of the subject. The reference sensorunit 130 is a sensor that is attached to the other breast of the subjectat a position corresponding to that of the one breast to which themeasurement sensor unit is attached to the subject and measures abiological signal of the subject. Here, for example, correspondingpositions are a position to be measured on the left breast and aposition to be measured on the right breast. Here, the term “positionscorresponding to each other” refers to the same positions in the leftand right breasts with respect to a center of the left breast and acenter of the right breast. That is, two corresponding points in theleft breast and the right breast have the same angle and distance from acenter point of the left breast and a center point of the right breast,respectively. For example, as shown in FIG. 12, a location of a fourthsensor 4 in the left breast and a location of a fifth sensor 5 in theright breast correspond to each other and correspond to the samepositions in both breasts.

The measurement sensor unit 110 and the reference sensor unit 130measure a biological signal at a first position to be measured and abiological signal value at a second position that corresponds to thefirst position, and measure a difference between voltage values at thefirst and second positions. It is rare that tumors appear in breastcells at the same positions in both breasts. As discussed above, thesame positions in both breasts refer to two corresponding points in theleft and right breasts.

Accordingly, when there is substantially no difference between voltagesmeasured at specific positions of both breasts, it indicates that cellsat the positions are highly unlikely to be tumor cells. In such cases,it is interpreted that the voltages at specific positions of bothbreasts are generated by normal cells.

On the other hand, when the measurement sensor unit 110 is attached to apart which has breast cancer or a breast tumor, the reference sensorunit 130 is attached at a position corresponding to that part and twobiological signal values are measured, it is very likely that the twovalues will not match. Based on the above characteristics (e.g.,similarity or difference between two values measured from correspondingpositions of breasts), components included in the portable breast cancerdetecting apparatus 1000 may easily determine whether a tumor is benignor malignant.

A plurality of peripheral sensor units 120 may be arranged around themeasurement sensor unit 110 to obtain higher accuracy. At least one orthe plurality of peripheral sensor units 120 are attached around themeasurement sensor unit 110 that is attached to the one breast to bemeasured and a biological signal value at the attachment area ismeasured to correct the biological signal value measured by themeasurement sensor unit 110 to be more accurate.

As shown in FIG. 5, one exemplary portable breast cancer detectingapparatus 1000 includes an overvoltage/overcurrent protection circuit210, a first amplifier, a ground operating circuit 300, an activefilter, a second amplifier, and an AD converter 250. The portable breastcancer detecting apparatus 1000 may be electrically connected to thesensor unit 100.

The portable breast cancer detecting apparatus 1000 measures abiological signal of a subject using the sensor unit 100 of a breastcancer diagnostic screening device. The portable breast cancer detectingapparatus 1000 may be connected to the sensor unit 100 configured tomeasure a biological signal around a breast of the subject.

The overvoltage/overcurrent protection circuit 210 is a component thatis attached to one side of the chest (or breast) of the subject awayfrom the sensor unit 100 attached to a measurement area of a breast, andprotects the device from causing an error, for example, an error due tostatic electricity, when a current is measured by the sensor unit 100,and also prevents an external high voltage/current that may be generatedin the screening device from flowing into a human body. In general, theovervoltage/overcurrent protection circuit 210 may include componentsthat satisfy standards of electrical safety. A plurality ofovervoltage/overcurrent protection circuits 210 may be provided incorrespondence to the measurement sensor unit 110, the plurality ofperipheral sensor units 120, and the reference sensor unit 130 so thatbiological signals measured by the measurement sensor unit 110, theplurality of peripheral sensor units 120 and the reference sensor unit130 primarily pass through the overvoltage/overcurrent protectioncircuits 210 when voltages corresponding to the biological signals areapplied to an inside of a circuit of the portable breast cancerdetecting apparatus 1000.

The first amplifier amplifies a voltage signal that is input through thesensor unit 100. Generally, since a potential difference generatedaccording to activity of cell tissue has a low level that is several mV,a level of a voltage may be amplified to obtain a meaningful measurementresult.

One exemplary embodiment of the first amplifier may include adifferential amplifier 220. The differential amplifier 220 is afunctional block of an integrated circuit (IC) and is used as anoperational amplifier and a comparator IC input end. The differentialamplifier 220 includes two input terminals and two output terminals andamplifies a difference between two input signals. The differentialamplifier 220 may be implemented by a BJT or a MOSFET, and may beconfigured as an emitter-coupled differential source, an active load,and various combinations thereof in the form of a block.

Two signals input to the differential amplifier 220 include a biologicalsignal value that is measured by the measurement sensor unit 110attached to one breast and a biological signal value that is measured bythe reference sensor unit 130 attached at a position correspondingthereto. As an example, when levels of the two biological signalsapplied to the two input terminals of the differential amplifier 220 arethe same or have substantially the same value, a difference between thetwo voltages is measured as being 0 or a value close to 0. Since thedifference between two voltages is zero or very small, a differentiallyamplified value is measured as being a very small value.

On the other hand, when the two levels of the biological signals appliedto the two input terminals of the differential amplifier 220 aredifferent from each other, there is a difference between the twovoltages. When the difference is amplified, it becomes greater than alevel obtained by amplifying the difference between the two voltagesthat is zero or is measured as being a very small value.

Also, sources of the biological signals applied to the two inputterminals may be biological signals that are measured by the pluralityof peripheral sensor units 120 instead of the measurement sensor unit110, and a biological signal that is measured by the reference sensorunit 130. The plurality of peripheral sensor units 120 are attachedaround one breast to which the measurement sensor unit 110 is attached,and when the plurality of peripheral sensor units 120 are attached to anormal cell, a value measured by the reference sensor unit 130 andvalues measured by the plurality of peripheral sensor units 120 are thesame or substantially the same, and thus may be measured as relativelysmall values even though they are amplified by the differentialamplifier 220. On the other hand, when the plurality of peripheralsensor units 120 are arranged on areas which have breast cancer cells ortumor cells, there is a difference between values of the two inputsapplied to the differential amplifier 220. Since the above operation issimilar to the principle described in the measurement sensor unit 110,additional description thereof will be omitted.

The portable breast cancer detecting apparatus 1000 according to anexemplary embodiment may include one differential amplifier 220, orinclude a plurality of differential amplifiers 220. The plurality ofdifferential amplifiers 220 amplify potential differences between themeasurement sensor unit 110 and the reference sensor unit 130 and theplurality of peripheral sensor units 120 and the reference sensor unit130 and transmit a corresponding signal to the active filter.

As shown in FIG. 6, the ground operating circuit 300 of the portablebreast cancer detecting apparatus 1000 according to an exemplaryembodiment may include an OP amp 310, a reference voltage Vref 320,capacitors C1 and C2, and a resistance RL. The OP amp 310 refers to anoperational amplifier. One exemplary OP amp 310 includes two inputterminals that are respectively electrically connected to thedifferential amplifier 220 and the reference voltage 320. A right legsignal output end is not separately electrically connected and an openloop is formed to rapidly stabilize a plurality of biological signalsmeasured by the portable breast cancer detecting apparatus 1000. In anopen loop state, the reference voltage 320 is not directly connected tothe first amplifier, more specifically, to the differential amplifier220, and is connected to the OP amp 310. The OP amp 310 may restrict aflow of a current and block a change in the reference voltage 320 forprotection.

One example of the portable breast cancer detecting apparatus 1000 mayinclude the active filter. The active filter is a filter circuit thatincludes an active element, C, and R and uses an OP amp, and may bewidely used in a low frequency range (e.g., about 10 kHz or less). Theactive filter removes an insertion loss in the filter circuit and alsoappropriately amplifies a signal.

Types of active filters include a low pass filter (LPF), a high passfilter, a band pass filter, and a band stop filter. The LPF allows asignal having a cutoff frequency of a filter or less to passtherethrough. Unlike the LPF, the high pass filter allows a signalhaving a cutoff frequency of the filter or higher to pass therethrough.The band pass filter is a filter that allows signals between a lowerlimit frequency and an upper limit frequency to pass therethrough. Theband stop filter blocks only a signal of a specific range of frequencyand allows other frequency signals to pass therethrough.

The active filter used in the portable breast cancer detecting apparatus1000 may be a LPF (or an active LPF) 230. The LPF 230 is provided toremove high frequency noise. Among biological signals of 50 Hz generatedin a bioelectromagnetic field, a biological signal associated withcarcinogenesis has a low frequency band. Therefore, a LPF configured toblock a frequency band of a corresponding band or higher may be used sothat a frequency band of 50 Hz or higher is filtered. Therefore, a passband ripple of the active LPF 230 of the portable breast cancerdetecting apparatus 1000 may be regulated to 0.5 dB or less, and a 3 dBcut off frequency may be about 50 Hz. Although a signal having afrequency greater than 50 Hz may pass through the active LPF 230, thesignal having a frequency greater than 50 Hz has a larger amount ofattenuation than that of a frequency of less than 50 Hz, and thus thesignal having a frequency greater than 50 Hz is difficult tosubstantially influence a signal system.

As shown in FIG. 7, a circuit of the active LPF 230 may include areference voltage Vref, a capacitor C1, resistances R1, R2, and R3, andan active LPF element 231. The active LPF element 231 may compensate fora loss of signal power generated in a passive LPS and also amplify asignal that passes through the LPF 230. An output signal input to S1from the differential amplifier 220 may be amplified as an output signalof S2 through the active LPF element 231, and an amplification ratiothereof is theoretically S2/S1=(R1+R3)/R1. A capacitor C3 may be used toregulate a value of a frequency signal that passes through the activeLPF element 231. A pass frequency (f) is 1/(R3×C3). Resistances andcapacitors respectively having various R3 values and C3 values may beused in combination to regulate a frequency to 50 Hz.

Also, in an exemplary embodiment, the LPF element 231 used in theportable breast cancer detecting apparatus 1000 may be a Chebyshev typeequally ripple filter. Alternatively, Butterworth type, Bessel/Gaussiantype, and elliptic type active filters may be used. However aButterworth filter has a problem in that it is difficult to obtain asignificant attenuation characteristic in an attenuation band eventhough the Butterworth filter has a flat characteristic in a pass band.A Bessel filter has a problem similar to the Butterworth filter in thatit is difficult to obtain a significant attenuation characteristic. AChebyshev type filter, which is useful when a return loss ripple andpassband attenuation are not important, is appropriately used as theactive filter of the portable breast cancer detecting apparatus 1000.The Chebyshev type filter has a characteristic in that a low passresponse has attenuation due to a ripple in a block frequency and thesame attenuation ripple occurs in a pass band, and a significantattenuation characteristic is obtained in an attenuation band.

The second amplifier is used to amplify only a voltage signal in a lowfrequency band of 50 Hz or less that has passed the active filter. In anexemplary embodiment, the second amplifier is a driver amplifier 240. Amain function of the driver amplifier 240 is to electrically separate ananalog end that mainly amplifies a biological signal and a digital endstarting from an AD converter and stably transmit the amplifiedbiological signal to the digital end. One exemplary driver amplifier 240may have has a common-mode rejection ratio (CMRR) of at least 60 dBwithin 50 Hz, and gains having a linear characteristic from 1 to 100 in0 to 50 Hz bands may be used in a linear characteristic of a largesignal gain ratio and a linear characteristic of a small signal gainratio.

As shown in FIG. 8, a driver amplifier element 241 serves as a link thatconnects an analog end that amplifies a biological signal and a data endthat converts the signal into a digital signal for processing data. Thedriver amplifier element 241 electrically separates an input signal S2and an output signal S3. An amplification ratio (S3/S2), which is aratio between the input signal S2 and the output signal S3, may beregulated by resistance values R4 and R5, and the ratio is (R4+R5)/R4.One exemplary driver amplifier may perform regulation so that a signalis always transmitted from an input end to an output end and there is noinfluence on the input signal S2 even when the output signal S3 ischanged without being linked to the input signal S2.

A range of a biological signal to be measured is −7 mV to 20 mV, and themeasured value is amplified to 0 to 4 V, which is an operating voltageof an AD converter, to correspond to the range of the biological signal.As a result, when the signal has passed through various amplificationmodules of the screening device, an amplification ratio of a biologicalanalog signal may be about 200. The operating voltage described in anexemplary embodiment is only an example. The operating voltage of the ADconverter is not limited to 4 V, and may be greater than or less than 4V and support a conversion resolution of the AD converter. A resolutionused in the exemplary embodiment is 1024, and a resolution of about 4mV/bit is provided. In such a configuration, a biological signal inputgreater than 20 mV and −7 mV or less is saturated at an amplificationend and is output as a signal of 0 V to 4 V, which refer to a lowerlimit value and an upper limit value. Such conversion details aresummarized in the following Table 1.

TABLE 1 Differential signal S3 signal AD converter AD converter Level(mV) level (V) binary number hexadecimal number −7 0 0000000000 000 0 10100000000 100 7 2 1000000000 200 14 3 1100000000 300 20 4 11111111113FF

All amplification processes may be designed to obtain an amplificationratio of about 200 in a plurality of signals of 50 Hz or less. Sincesignal distortion may occur due to a linear characteristic of a devicewhen a specific amplification process is performed at the amplificationratio of 200, multiple amplification processes may be performed.However, when there are excessive number of amplification processes, asignal-to-noise ratio may be deteriorated due to thermal noise. Thus,providing efficient amplification step is desirable. In an exemplaryembodiment, three amplification processes may be used, and amplificationratios of the differential amplifier to the driver amplifier are asfollows.

-   -   Differential amplifier: 15    -   Active low pass filter: 13.4    -   Driver amplifier: 1

An overall amplification ratio obtained through the above modules isabout 201.00. According to a characteristic and a tolerance of a devicethat is actually used, an amplification ratio is designed to have 201 ±an error of 2%.

The AD converter 250 converts an analog voltage signal transmitted fromthe second amplifier into digital data that can be processed in a dataprocessing unit. According to an exemplary embodiment, 10-bit analogdigital conversion is performed in the AD converter 250, and aconversion rate may be 200 times/sec or less for each channel. Thedigital data converted in the AD converter 250 is transmitted to a dataprocessing unit 260. Alternatively, the AD converter 250 and the dataprocessing unit 260 may be integrated.

Referring again to FIG. 8, a signal S3 output from the second amplifiermay be transmitted to the AD converter 250 and converted into rawdigital data having a resolution of 10 bits. For example, the signal maybe converted into a hexadecimal number and converted into a value of 0to 3FF. The signal S3 is converted by the AD converter 250 according toa voltage level thereof, and may be set in a system memory unit (notshown) in the data processing unit 260 so that conversion is performedin the same method as in the following Table 1. The converted data ischanged according to data formats shown in the following Table 2 forstorage and is transmitted to a server. Regarding Tables 2 and 3 below,a real time compression process is performed on the 10-bit data given inTable 1 so that five pieces of biological data are converted into onepacket. The reason why compression in Table 2 is performed is asfollows. Since wireless bandwidths of a wireless network between ascreening device and a smart device, and a wireless network between thesmart device and a mobile communication base station may besubstantially changed according to an environment, data is compressedinto one packet in order to transmit and receive the data reliably. Abandwidth of datagrams shown in Table 2 is 11 bytes×200 =220 bytes/sec.As an example, a module used as a wireless communication unit usesBluetooth 3.0 technology to transmit data to a smart device, but theexemplary embodiments are not limited thereto.

TABLE 2 Byte order Bit structure Description Notes 1 0PPP PPPX PACKETThe number of 2 0XXX XXXX HEADER transmitted packets 3 0AAA AAAA CHANNEL0 LSB Target signal 4 0BBB BBBB CHANNEL 1 LSB Peripheral signal 1 50AAA-BBB CHANNEL 0 &1 Target signal and MSB peripheral signal 1 6 0CCCCCCC CHANNEL 2 LSB Peripheral signal 2 7 0DDD DDDD CHANNEL 3 LSBPeripheral signal 3 8 0CCC-DDD CHANNEL 2 &3 Peripheral signal 2 MSB andperipheral signal 3 9 0EEE EEEE CHANNEL 4 LSB Peripheral signal 4 100FFF FFFF CHANNEL 5 LSB Channel 5 reserved. 11 1EEE-FFF CHANNEL 4 & 5Peripheral signal 4 MSB

TABLE 3 Description 1, 0: SYNC bit. MSB is set to “1” when the last byteof a packet is transmitted P: 6-bit packet counter X: auxiliary channelbyte A to F: 10-bit data value obtained through 0 to 5 channel —: notused, set to “0.”

FIG. 9 is a screen showing a form of a signal that is input to the dataprocessing unit 260 through the AD converter and a stabilized signalthat has passed through an eighth order low pass digital filter.

As shown in FIG. 9, the data converted through the AD converter 250 istransmitted to the data processing unit 260. The converted data isprocessed in the data processing unit 260 by a digital filter. Forexample, the digital filter may be implemented as software, hardware,and/or a combination thereof.

The data can be processed through the differential amplifier 220.However, in this case, there is a problem in that the size of the deviceincreases. Therefore, according to an exemplary embodiment, the minimumnumber of functions that are difficult to be performed by software maybe processed by hardware, and the other functions may be implemented bysoftware. An exemplary digital filter according to an exemplaryembodiment may be an eighth order low pass Chebyshev filter but theexemplary embodiments are not limited thereto. Since S3 signals that areinput to the AD converter 250 through the driver amplifier 240 havewidths of constant heights, when signals overlap, there is a problem inthat it is difficult to determine an accurate value. When the signalpasses through the filter, the signal is converted into a moresimplified signal.

FIGS. 10 and 11 are flowcharts illustrating a process of transmitting asignal passing through a digital filter of the data processing unit 260to a computation unit (or a controller) 270 and examining a lesion inthe computation unit 270 according to an exemplary embodiment. FIGS. 12and 13 are schematic diagrams showing processes performed by a pluralityof sensor units according to an exemplary embodiment to determine arelative position with respect to a position of a malignant tumor andmeasure a biological signal.

Although not shown in the drawings, the computation unit 270 may includea measured value average calculation module, a sensor positioncorrection module, a sensor failure checking module, and a lesionprimary screening module (or a lesion determination controller).

Terms described in FIGS. 10 and 11 are defined as follows.

Dn: a value of a signal of an n-th sensor after the signal passesthrough a digital filter (for example, n=1 indicates a 1^(st) sensor,and n=2 indicates a 2^(nd) sensor)

Δt: one time interval of 5 msec during which Dn is read

N(At): the number of time intervals of Δt. 100 msec (or 0.1 second) whenN is 20

t: the number of units of 100 msec. For example, a value of t for 3minutes is 10×60×3=1800 times

An(Δt): an average value of Dn values that are input during the timeinterval t

An(t): an average value of 20 values of An(t)

A: an average value of An(t) values at t=1800. t=1800 indicates thenumber of t values for 3 minutes

Vn(At): Dn(At) value when a difference from An(At) exceeds ±3.5 mV

++: a value of a corresponding variable is increased by one (e.g., t++:t=t+1)

Err_flag(n): the number of times an n-th sensor value exceeds adetermined range. Err_flag(n) indicates whether there is a contactfailure and/or whether there is a sensor failure when the number oftimes the n-th sensor exceeds a determined range exceeds 20% of thetotal number of measurements M.

M: the total number of measurements t×200×60 seconds×3 minutes

AV(n): average value of Vn values

LF: line failure

LO: line overload

In FIG. 10, an average value of values other than the maximum value andthe minimum value among signal values obtained from a specific sensorunit (for example, the measurement sensor unit 110) that are sampled inthe measured value average calculation module 271 is computed in themeasurement sensor unit. More specifically, as shown in FIG. 9, Dnindicates a signal value in an n-th sensor after the signal passesthrough a digital filter. When the computation starts, an average valueof the values other than the maximum value and the minimum value among aplurality of signals that are input during a time interval (t=5 msec) inwhich all Dn values are read at once is computed. In the followingprocess, the process advances to the next process only when a differencebetween An(t), which is an average value of signals in the n-th sensor,and Dn, which is a signal value in the n-th sensor, is ±3.5 mV or less.When the difference exceeds ±3.5 mV, the value is considered to be Vn,and an average value of the Dn values other than the value is computedagain. This means that, when there is a wrong input from one sensor, theinput is ignored. The considered Vn value is used for an algorithm fordetermining whether there is a contact failure and whether there is asensor failure in FIG. 10.

Dn is read 200 times a second and an average An(t) is computed every 20times that Dn is read (e.g., every 100 msec). A biological signal to bemeasured is a signal generated when a cell is differentiated and isconsidered as a low speed analog signal whose state does not sharplychange. A signal of 50 Hz or less may be measured in units of 10 msec.However, in an exemplary embodiment, a signal having ambiguousregularity may be sampled at least three times. In consideration of foursamplings, a signal of 50 Hz or less is converted into a digital signalin 5 msec. An average of the converted signals is obtained every 20times that a signal is converted and a change in the biological signalis appropriately traced in units of 100 msec. Therefore, An(t), which isan average value for t time interval (5 msec), is computed.

When an An(t) value is measured 20 times, An(t), which is an averagevalue of the values, is computed. Here, the An(t) value may beinterpreted as an average value of biological signals measured for 0.1seconds. Again, 0.1 seconds is used as one unit (t) to more accuratelyconfirm whether there is a breast cancer lesion, and an average value ofAn(t) values is computed to compute an average value for a time forwhich a screening device is attached to a subject. The portable breastcancer detecting apparatus 1000 according to an exemplary embodimentmeasures a biological signal of a corresponding area for, for example, 3minutes, t=1800 is computed, and A, which is an average value of An(t)values computed every 0.1 seconds, is computed. The average value A canbe used to determine whether there is a lesion.

FIG. 11 to FIG. 13 show an algorithm for interpreting data obtained byaveraging and schematic diagrams for describing the same. FIGS. 12 and13 show that, when there is a subcutaneous lesion, values of An(t)measured at skin closest thereto and in the vicinity thereof aresimilar.

Referring to FIG. 11, in the algorithm for determining whether there isa contact failure in a sensor and whether there is a sensor failure,when a signal value measured by a specific sensor unit (e.g., ameasurement sensor unit or a peripheral sensor unit) is different from asignal value measured by the reference sensor unit 120 and an allowablerange exceeding Err_flag(n), which is a value exceeding ±3.5 mV, exceeds20% of the total number of measurements M, a position at which a sensoris attached is determined to be corrected. In this case, the position ofthe sensor needs to be corrected, and measurements need to be performedagain.

Also, when measurement is performed as being less than a referencevoltage, a Dn value exceeding ±3.5 mV based on An(t) is considered to bea Vn value and an average value of the Vn value in a time interval t iscomputed as AV(n). When the AV(n) value is computed to be less than −6mV, a sensor of the sensor unit is considered to have a defect and thesignal is set to be transmitted to a sensor failure checking unit. Whentwo or more sensors within a plurality of sensor units are determined tohave a value of less −6 mV, a line failure is determined, and thus asensor replacement message may be shown.

When a difference between An(t), which is an average value for each timeinterval t, and a Dn value is less than ±3.5 mV, a signal may betransmitted to the lesion primary screening module to perform primaryscreening of a lesion. On the other hand, when the difference is ±3.5 mVor greater, it is determined that a position at which a sensor isattached needs to be corrected. In this case, to determine whether thereis a line overload (LO), when a difference between AV(n), which is anaverage value of Vn values, and A is 7 mV or greater, the difference isdetermined as a line failure (LF) of a sensor and a change message isshown to suggest arranging an attached target sensor between peripheralsensors. When a difference between AV(n), which is an average value ofVn values, and A is from 3.5 to less than 7 mV and three or more sensorsare determined to have a line overload, a change message may be shown tosuggest arranging a target sensor between peripheral sensors. That is,when two or more sensor units are determined to be corrected, a positionat which a sensor unit is attached is determined to be erroneous, and achange message may be shown to suggest changing the position of thesensor to be changed. This is based on the fact that, even when there isa lesion, the presence of the lesion may be interpreted as being at aposition distanced away from a position at which a target signal ismeasured.

Details of determining an algorithm based on the above procedures willbe described with reference to FIG. 12 and FIG. 13.

In FIG. 12, when there is a subcutaneous tumor, a first sensor 1indicates a target signal measurement position that is closest to thetumor. Second and third sensors 2 and 3 indicate peripheral signalmeasurement positions. When the breast is considered to have anelliptical structure, a biological signal of a tumor can be measured inperipheral signal measurement positions in addition to the target signalmeasurement position, although a level of the signal may be slightlylower than that in the first sensor. However, in a fourth sensor 4,since a level of a signal of the lesion is low, it is difficult todistinguish the signal from a normal biological signal and accordinglythe signal may be measured as a normal signal. When the size of thetumor increases, the tumor may be measured as being greater than anormal range of a size in the fourth sensor 4. When screening isperformed while an accurate position of the lesion is not identified, itmay be reasonable to exclude the minimum value of attached sensors,which is reflected in the algorithm. In consideration of the fact thatthe maximum value can be an instantaneous value according tocharacteristics of biological signals, the maximum value may also beexcluded by the algorithm. For example, generation of biological signalsdue to activity of nerve cells at the measurement position, andgeneration of biological signals due to natural muscular contraction andrelaxation are natural. Therefore, the maximum value and the minimumvalue may be excluded and the remaining signals are averaged forscreening breast cancer (refer to FIG. 10)

Referring to FIGS. 12 and 13, a fifth sensor 5 (or the reference sensorunit, 120) is attached to a position symmetric to the first sensor 1 (orthe measurement sensor unit, 110). In the fourth sensor 4, as the sizeof tumor increases in one breast (e.g., left breast), a signal is likelyto be measured. However, in the fifth sensor 5, it is not easy tomeasure a biological signal of breast tumor of the other breast (e.g.,right breast). That is, when a value of differences between the first,second, third, and fourth sensors 1-4 based on the fifth sensor 5 iscalculated, there is a significant difference in the lesion. In theexemplary embodiments, the breast lesion may be screened based on thisprinciple.

When the number of cases in which a Vn value is obtained is 20% or lessof the total number of measurements (M), a primary screening may beperformed on a lesion. When an average value (A) of all sensor signalsis 7 mV or less, the lesion is determined to be normal, and are-screening may be recommended a regular screening day (for example, ata one month interval). When the average value (A) is from 7 to less than14 mV, the lesion is determined to be a tumor related to breast cancerand re-measurement is recommended after, for example, a short time(e.g., after two days) using a screening device again. When the averagevalue (A) is measured as 14 mV or greater, the lesion is determined tobe negative, and an instruction for recommending a re-screening foraccurate confirmation after three days may be shown.

The data obtained as above will be summarized again as follows.

1. When a signal value measured by the measurement sensor unit 110 isthe same as a signal value measured by the reference sensor unit 120,cell tissue activities of left and right breasts are the same orsubstantially the same.

2. When the signal value measured by the measurement sensor unit 110 isgreater than the signal value measured by the reference sensor unit 120,cell tissue activity in a corresponding signal area is high.

3. Unlike case 2, when the signal value measured by the measurementsensor unit 110 is smaller, cell tissue activity is low. However, whenthe signal value measured by the measurement sensor unit 110 iscontinuously measured as being 0 at 20% or greater, the signal value isset and determined to be a contact failure in a “sensor” or a “sensorfailure,” and corresponding data is entirely ignored.

3-1. Further, when case 3 occurs in two or more sensor units, sensorsare replaced and measurement is performed again.

3-2. When case 3 occurs again, positions of the reference sensor unit120 and the measurement sensor unit 110 are changed and measurement isperformed again.

<Basic Assumptions for Interpretation of a Breast Cancer Lesion Based onData>

1. Left and right activities at corresponding positions on breastshaving no breast cancer lesion are the same or substantially the same.

2. It is assumed that there is no probability or substantially noprobability of the same lesion developing at positions that correspondto each other at left and right breasts. As discussed above, the term“positions corresponding to each other” refers to the same positions inthe left breast and the right breast that have the same angle anddistance from a center point of the left breast and a center point ofthe right breast, respectively.

3. A position of the measurement sensor unit 110 may not accuratelymatch a position of a subcutaneous lesion.

4. A screening result is determined as being normal, requiringre-screening, or being abnormal. Values of −7 to 20 mV are divided intofour groups and may be used to determine whether there is a lesion asfollows. Values in parentheses below indicate decimal values.

1) 0 mV or less (0 or less): normal (however, in consideration of apossibility of a contact failure in a sensor or a sensor failure,positions of the measurement sensor unit 110 and the reference sensorunit 120 are changed and measurement is performed again)

2) 0 to 7 mV (0 to 511.5): normal

3) 7 to 14 mV (511.5 to 767.25): re-screening

4) 14 to 20 mV (767.25 to 1023): abnormal

The portable breast cancer detecting apparatus 1000, shown in FIG. 5,may not include the computation unit 270. In this case, a signal thatpassed through a digital filter of the data processing unit 260 may betransmitted to a terminal 400 including the computation unit 270, forexample, a smartphone, a computer, and a notebook, using a Bluetoothmodule 280, and is computed through the computation unit 270. When theapparatus 1000 include the computation unit 270, the terminal 400 stillmay be used to as a separate device which can share and synchronize thedata with the apparatus 1000.

The signal may be transmitted to the terminal 400 through wirelesscommunication using the wireless communication unit. The wirelesscommunication unit may include a short-range communication module and awireless Internet module. A wireless signal includes various formats anddata according to message transmission and reception between a probe anda smart device. The wireless Internet module is a module for wirelessInternet, and a WLAN, Wibro, Wimax, HSDPA, an LTE dongle, and the likemay be used. The short-range communication module is a module forshort-range communication. As a short-range communication technology,the Bluetooth module 280, UWB, ZigBee, and the like may be used, andparticularly, a communication technology compatible with smart devicesis preferentially used.

As an example, the result obtained by the portable breast cancerdetecting apparatus 1000 of the exemplary embodiments can be stored anddisplayed through the application installed in the terminal 400. FIG. 14to FIG. 17 show interface screens in which a screening result of datameasured by the portable breast cancer detection apparatus of theexemplary embodiment is confirmed using the application. Gradient colorcharts can be used to interpret results values consistently. The chartsshow signal values obtained by the measurement sensor unit and resultsmeasured through the peripheral sensor units. An X axis represents atime and a Y axis represents data-converted biological signal values.FIG. 14 shows an interface screen before diagnosis starts. FIG. 15 toFIG. 17 are interface screens showing results values after diagnosis.FIGS. 15 and 16 show results determined as being normal. FIG. 17 showsresults determined as lesion (e.g., breast cancer) being present.

In the portable breast cancer detection apparatus according to theexemplary embodiments, measurement is directly performed on a breastusing one of measured signals as a reference signal instead of a rightleg signal.

According to a configuration of the above device, there is no need toset a separate ground position at a human body, a distance of ameasurement position is shortened, and an impedance between measuredsignals is decreased. Therefore, it is possible to stabilize a signal ina short time.

Also, there is no damage to a human body since the measurement method isnon-invasive and screening can be performed in a short time, and themeasurement method is very efficient in consideration of time and cost,precise screening of a test area is made by regulating the number ofsensors, and it is possible to minimize a misdiagnosis.

At least one of the components, elements, modules or units representedby a block as illustrated in the drawings may be embodied as variousnumbers of hardware, software and/or firmware structures that executerespective functions described above, according to an exemplaryembodiment. For example, at least one of these components, elements orunits may use a direct circuit structure, such as a memory, a processor,a logic circuit, a look-up table, etc. that may execute the respectivefunctions through controls of one or more microprocessors or othercontrol apparatuses. Also, at least one of these components, elements orunits may be specifically embodied by a module, a program, or a part ofcode, which contains one or more executable instructions for performingspecified logic functions, and executed by one or more microprocessorsor other control apparatuses. Also, at least one of these components,elements or units may further include or implemented by a processor suchas a central processing unit (CPU) that performs the respectivefunctions, a microprocessor, or the like. Two or more of thesecomponents, elements or units may be combined into one single component,element or unit which performs all operations or functions of thecombined two or more components, elements of units. Also, at least partof functions of at least one of these components, elements or units maybe performed by another of these components, element or units. Further,although a bus is not illustrated in the above block diagrams,communication between the components, elements or units may be performedthrough the bus. Functional aspects of the above exemplary embodimentsmay be implemented in algorithms that execute on one or more processors.Furthermore, the components, elements or units represented by a block orprocessing steps may employ any number of related art techniques forelectronics configuration, signal processing and/or control, dataprocessing and the like.

Although a few embodiments have been shown and described, it would beappreciated by those skilled in the art that changes may be made inexemplary embodiments without departing from the principles and spiritof the disclosure, the scope of which is defined in the claims and theirequivalents.

What is claimed is:
 1. A portable breast cancer screening devicecomprising: a measurement sensor configured to measure a biologicalpotential in a first breast area of a subject; a reference sensorconfigured to measure a biological potential in a second breast areacorresponding to a position at which the measurement sensor is attached;and a detector electrically connected to a peripheral sensor configuredto measure a biological potential around the position at which themeasurement sensor is attached, and configured to measure a biologicalpotential generated in a body, wherein the detector comprises: anovervoltage/overcurrent protection circuit configured to block a leakagecurrent from being introduced to the detector; a differential amplifierconfigured to amplify a voltage input from a sensor among themeasurement sensor, the reference sensor, and the peripheral sensor; anactive low pass filter configured to pass only a signal frequency of alow frequency band among signals transmitted from the differentialamplifier; a driver amplifier configured to amplify a signal passedthrough the active low pass filter; an analog-to-digital (AD) converterconfigured to convert the signal amplified by the driver amplifier intoa digital signal; and a ground operating circuit electrically connectedto the differential amplifier, wherein the ground operating circuitcomprises: an operational amplifier having two input terminals that areelectrically connected to the differential amplifier and a referencevoltage, respectively; a resistor electrically connected between theoperational amplifier and an output voltage; a first capacitorelectrically connected between the differential amplifier and the outputvoltage; and a second capacitor electrically connected between theoperational amplifier and the output voltage.
 2. The portable breastcancer screening device according to claim 1, wherein the differentialamplifier is further configured to amplify a difference between twovoltages when biological potential values measured by the measurementsensor and the reference sensor are input thereto.
 3. The portablebreast cancer screening device according to claim 1, wherein thedifferential amplifier amplifies a voltage of a difference betweenbiological potential values measured by the peripheral sensor and thereference sensor.
 4. The portable breast cancer screening deviceaccording to claim 1, wherein a part of the ground operating circuit isof an open loop type.
 5. The portable breast cancer screening deviceaccording to claim 1, wherein the ground operating circuit iselectrically connected to a plurality of differential amplifiers.
 6. Theportable breast cancer screening device according to claim 1, whereinthe signal frequency of the low frequency band is 50 Hz or less.
 7. Theportable breast cancer screening device according to claim 1, furthercomprising: a controller electrically connected to the AD converter andconfigured to store an algorithm for calculating the digital signalconverted by the AD converter and confirming a breast cancer lesion. 8.The portable breast cancer screening device according to claim 7,wherein the controller is further configured to: measure an averagevalue of measured sensor signals; compute a signal value that exceeds anallowable range and determine whether to change a position at which thesensor among the measurement sensor, the reference sensor, and theperipheral sensor is attached; determine a failure in the sensor amongthe measurement sensor, the reference sensor, and the peripheral sensor;and confirm an average value of sensor signals having no error anddetermine whether a lesion is benign.
 9. The portable breast cancerscreening device according to claim 8, wherein, when a differencebetween An(t), which is an average value of signals for each certaintime interval (t), and a specific signal value (Dn) among a plurality ofsignal values input for t is equal to a specific value or greater, thecontroller excludes the signal value from a computation of an averagevalue of the signals.
 10. The portable breast cancer screening deviceaccording to claim 8, wherein the controller determines whether tochange the position at which the sensor among the measurement sensor,the reference sensor, and the peripheral sensor is attached when anumber of sensings of a value (Vn) exceeding ±3.5 mV from an averagevalue An(t) of signals for each certain time interval (t) is a certainratio or higher with respect to a total number of sensings (M).
 11. Theportable breast cancer screening device according to claim 8, whereinthe controller determines the failure in the sensor among themeasurement sensor, the reference sensor, and the peripheral sensor whena number of sensings of a value (Vn) exceeding ±3.5 mV from an averagevalue An(t) of signals for each certain time interval (t) is a certainratio or higher with respect to a total number of sensings (M).
 12. Theportable breast cancer screening device according to claim 8, whereinthe controller determines a difference of an average value (A) of allsignal values measured in the sensor among the measurement sensor, thereference sensor, and the peripheral sensor to be normal when thedifference is less than 7 mV, indicates suggestion of re-screening whenthe difference is 7 mV or greater and less than 14 mV, and determinesthe average value (A) to be abnormal when the difference is from 14 mVto 20 mV.
 13. The portable breast cancer screening device according toclaim 1, wherein the first breast area and the second breast arearespectively correspond to areas on a skin of the subject.